Circadian Disruption Impacts Fetal Development in Mice Using High-Frequency Ultrasound.

The developmental origins of health and disease theory suggests that environmental exposures during early life, particularly during prenatal life, can greatly influence health status later in life. Irregular light-dark cycles, such as those experienced during shift work, result in the repeated disruption of circadian rhythms, which negatively impacts physiological and behavioral cycles. The purpose of our study was to assess parameters in the developing mouse embryo and fetus using high frequency ultrasound when exposed to circadian disruption. Pregnant female mice were subjected to a seven-hour advanced circadian disrupted protocol or remained on a normal 12/12 light-dark cycle throughout pregnancy. Significant differences were observed in placental length (p = 0.00016), placental thickness (p = 0.0332), and stomach diameter (p = 0.0186) at E14.5-18.5. These findings suggest that circadian disruption in pregnant dams, mimicking shift work, alters embryonic and fetal development in specific organs in utero.